Downregulation of microRNA-448 improves isoflurane-induced learning and memory impairment in rats

The Protective Effect of Picroside II on Isoflurane-Induced Neuronal Injury in Rats via Downregulating miR-195

INTRODUCTION

Numerous pieces of evidence demonstrated that isoflurane induces hippocampal cell injury and cognitive impairments. Picroside II has been investigated for its anti-apoptosis and antioxidant neuroprotective effects. We aimed to explore the protective effects of picroside II and the role of microRNA-195 (miR-195) on isoflurane-induced neuronal injury in rats.

METHODS

The Morris water maze test was used to evaluate the effects of isoflurane on rats regarding escape latency and time in quadrant parameters. Real-time quantitative PCR was used to detect the expression levels of miR-195 and pro-inflammatory cytokines, including inter-leukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) mRNA, in the hippocampal tissues and neuronal cells.

RESULTS

The picroside II significantly improves isoflurane-induced higher escape latency and lower time spent in the quadrant compared with the control rats. Picroside II also promotes cell viability and suppresses cell apoptosis of isoflurane-induced neuronal cells. Besides, picroside II suppresses the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and miR-195 in vivo and in vitro. Furthermore, overexpression of miR-195 abrogates the effects of picroside II on the expression of pro-inflammatory cytokines. The appropriate dose of picroside II is 20 mg/kg.

CONCLUSION

Picroside II could protect the nervous system possibly through inhibiting the inflammatory response in the isoflurane-induced neuronal injury of rats. The protective effect of picroside II may be achieved by downregulating the expression of miR-195 and then inhibiting the inflammatory response.

Transient Focal Cerebral Ischemia Leads to miRNA Alterations in Different Brain Regions, Blood Serum, Liver, and Spleen

Ischemic stroke is characterized by an occlusion of a cerebral blood vessel resulting in neuronal cell death due to nutritional and oxygen deficiency. Additionally, post-ischemic cell death is augmented after reperfusion. These events are paralleled by dysregulated miRNA expression profiles in the peri-infarct area. Understanding the underlying molecular mechanism in the peri-infarct region is crucial for developing promising therapeutics. Utilizing a tMCAo (transient Middle Cerebral Artery occlusion) model in rats, we studied the expression levels of the miRNAs (miR) 223-3p, 155-5p, 3473, and 448-5p in the cortex, amygdala, thalamus, and hippocampus of both the ipsi- and contralateral hemispheres. Additionally, the levels in the blood serum, spleen, and liver and the expression of their target genes, namely, Nlrp3, Socs1, Socs3, and Vegfa, were assessed. We observed an increase in all miRNAs on the ipsilateral side of the cerebral cortex in a time-dependent manner and increased miRNAs levels (miR-223-3p, miR-3473, and miR-448-5p) in the contralateral hemisphere after 72 h. Besides the cerebral cortex, the amygdala presented increased expression levels, whereas the thalamus and hippocampus showed no alterations. Different levels of the investigated miRNAs were detected in blood serum, liver, and spleen. The gene targets were altered not only in the peri-infarct area of the cortex but selectively increased in the investigated non-affected brain regions along with the spleen and liver during the reperfusion time up to 72 h. Our results suggest a supra-regional influence of miRNAs following ischemic stroke, which should be studied to further identify whether miRNAs are transported or locally upregulated.

miR-124-3p Ameliorates Isoflurane-Induced Learning and Memory Impairment via Targeting STAT3 and Inhibiting Neuroinflammation

INTRODUCTION

Substantial evidence has indicated that isoflurane leads to learning and memory impairment. This study was designed to investigate the potential role of microRNA-124-3p (miR-124-3p) in isoflurane-induced learning and memory impairment in rats.

METHODS

Spatial learning and memory of rats were estimated by the Morris water maze (MWM) test after the construction of isoflurane-treated models. qRT-PCR was performed to assess the expression levels of miR-124-3p. The levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampal tissues were determined by enzyme-linked immunosorbent assay. The luciferase activity was determined by using a dual-luciferase reporter assay system.

RESULTS

The higher escape latency and lower time spent in the original quadrant were shown in isoflurane-treated rats compared with the control rats. Moreover, treatment with isoflurane could induce neuroinflammation, and miR-124-3p was poorly expressed in the hippocampal tissue of isoflurane-treated rats. Furthermore, STAT3 is a functional target of miR-124-3p, and inflammatory cytokine level was downregulated by miR-124-3p.

DISCUSSION/CONCLUSION

Combining the results of the current study demonstrates that miR-124-3p may have pivotal roles in improving isoflurane-induced learning and memory impairment via targeting STAT3 and inhibiting neuroinflammation.

Silencing of miR-302b-3p alleviates isoflurane-induced neuronal injury by regulating PTEN expression and AKT pathway

Isoflurane (ISO) is an anesthesia and can result in neuron injury. A previous study has indicated that microRNA-302b-3p (miR-302b-3p) exerts a crucial function in modulating cerebral ischemia/reperfusion damage-induced neuronal injury. We sought to examine the role of miR-302b-3p in ISO-induced neuronal injury. In the present study, the effects of miR-302b-3p on ISO-induced neuron injury were investigated by MTT and TUNEL assays. We discovered that ISO stimulation led to miR-302b-3p upregulation and neuronal injury. MiR-302b-3p silencing exerted protective effects against ISO induced neuronal injury. In addition, phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was a direct downstream target gene of miR-302b-3p. MiR-302b-3p targets the 3'UTR of PTEN to inhibit its mRNA expression, and further reduces its protein expression. Silencing of PTEN partially reversed the protecting effects of silenced miR-302b-3p on ISO-induced injury of hippocampal neurons. Further, miR-302b-3p activated the AKT signaling pathway in neurons exposed to ISO by downregulation of PTEN. Finally, in vivo studies revealed that silencing of miR-302b-3p alleviates ISO-induced injury and spatial memory impairment of rats partly by upregulation of PTEN. Overall, our findings indicated that miR-302b-3p targets PTEN to activate the AKT pathway, and silencing of miR-302b-3p plays a neuroprotective role in ISO-induced neuronal injury by the PTEN/AKT pathway, suggesting miR-302b-3p as a crucial target for ISO-induced neuronal injury.

Isoflurane-induced expression of miR-140-5p aggravates neurotoxicity in diabetic rats by targeting SNX12

MicroRNAs (miRNAs) are widely known as critical regulators in isoflurane-induced neurotoxicity during the development of brain. Moreover, isoflurane could aggravate cognitive impairment in diabetic rats. The present study was designed to investigate the role and mechanism of miR-140-5p on isoflurane-induced neurotoxicity in diabetic rats. Firstly, a diabetic rat model was established by injection of streptozotocin (STZ) and identified by Morris water maze test. The result indicated that isoflurane treatment exacerbated STZ-induced cognitive impairment, as demonstrated by increase of the latency to the platform and decrease of the proportion of time spent in the target quadrant. Secondly, miR-140-5p was up-regulated in diabetic rats treated with isoflurane. Functional assays revealed that knockdown of miR-140-5p attenuated neurotoxicity in diabetic rats, which was shown by a decrease of the latency to the platform and an increase of the proportion of time spent in the target quadrant. Mechanistically, we demonstrated that miR-140-5p directly bonded to SNX12 (sorting nexin 12). At last, the neuroprotective effect of miR-140-5p knockdown against isoflurane-aggravated neurotoxicity in diabetic rats was dependent on up-regulation of SNX12 and inhibition of cell apoptosis. In summary, these meaningful results demonstrated the mitigation of miR-140-5p knockdown against isoflurane-aggravated neurotoxicity in diabetic rats via SNX12, suggesting a novel target for neuroprotection in diabetes under isoflurane treatment.

Neuroprotective effects of miR-142-5p downregulation against isoflurane-induced neurological impairment

Background

Isoflurane can lead to neuron damage to the developing brain, resulting in learning and memory disability. The aim of this study was to investigate the role of miR-142-5p on isoflurane-induced neurological impairment.

Methods

The Morris water maze (MWM) test was performed to evaluate spatial learning and memory of rats. The expression level of miR-142-5p was measured using qRT-PCR. MTT assay was used to calculate the viability of hippocampal neuronal cells. The cell apoptosis was analyzed using Flow cytometric assay.

Results

Isoflurane treatment led to the increase of neurological function score and escape latency, and the reduction of time spent in the original quadrant in rats. The expression level of miR-142-5p was increased significantly in isoflurane-treated rats. MiR-142-5p downregulation protected against isoflurane-induced neurological impairment, which was reflected by the decrease of neurological function score and escape latency, and the increase of time spent in the original quadrant. In vitro, downregulation of miR-142-5p alleviated isoflurane-induced neuron cell viability inhibition, and relieved isoflurane-induced cell apoptosis.

Conclusions

MiR-142-5p downregulation plays a neuroprotective role in protecting against isoflurane-induced neurological impairment through regulating neuron cell viability and apoptosis. It provides a theoretical basis for the investigation of the mechanism underlying the effect on isoflurane-induced neurological impairment.

LncRNA AFAP1-AS1 contributes to the progression of endometrial carcinoma by regulating miR-545-3p/VEGFA pathway

Endometrial carcinoma (EC) accounts for 20%-30% of female reproductive tumors. Targeted therapy for EC has shown great advantages with small side effects. To improve the survival of EC patients, more new therapeutic targets need to be found. Long non-coding RNAs (lncRNAs) are series of RNAs with over 200 nucleotides that regulate various cellular functions. LncRNA actin filamentin-1 antisense RNA 1 (AFAP1-AS1) is involved in the development of a variety of cancers, such as pancreas ductal adenocarcinoma and esophageal adenocarcinoma. However, it is not clear whether AFAP1-AS1 has any effects on EC or the exact regulatory mechanism. Herein, we found the high expression of AFAP1-AS1 in human EC tissues, and AFAP1-AS1 was correlated with EC patients' prognosis and clinical features. AFAP-AS1 could affect EC cell proliferation, migration, and invasion, and contributed to endothelial cell angiogenesis. We further showed that AFAP-AS1 could promote the expression of VEGFA through the adsorption of miR-545-3p, thus promoting the angiogenesis and invasion of EC, and contribute to tumor growth and metastasis in vivo. Thus, we thought AFAP1-AS1 had the potential to serve as an EC therapeutic target.

microRNA-124 attenuates isoflurane-induced neurological deficits in neonatal rats via binding to EGR1

Isoflurane anesthesia induces neuroapoptosis in the development of the brain. In this study, neonatal rats and hippocampal neurons were subjected to isoflurane exposure, in which the effect of miR-124 on the neurological deficits induced by isoflurane was evaluated. Isoflurane anesthesia models were induced in neonatal SD rats aged 7 days and then treated with miR-124 agomir, miR-124 antagomir, or LV-CMV-early growth response 1 (EGR1) plasmids. Then, the spatial learning and memory ability of rats were evaluated by Morris water maze. Furthermore, primary hippocampal neurons cultured 7 days were also exposed to isoflurane and transfected with miR-124 agomir, miR-124 antagomir, or LV-CMV-EGR1 plasmids. The targeting relationship of miR-124 and EGR1 was verified by the dual-luciferase reporter gene assay. To identify the effect of miR-124 on neuron activities, the viability and apoptosis of hippocampal neurons were assessed. In response to isoflurane exposure, miR-124 expression was reduced and EGR1 expression was increased in the hippocampal tissues and neurons. The isoflurane anesthesia damaged rats' spatial learning and memory ability, and reduced viability, and promoted apoptosis of hippocampal neurons. EGR1 was targeted and negatively regulated by miR-124. The treatment of miR-124 agomir improved rats' spatial learning and memory ability and notably increased hippocampal neuron viability and resistance to apoptosis, corresponding to an increased brain-derived neurotrophic factor (BDNF) expression, inhibited expression of proapoptotic factors (cleaved-Caspase-3 and Bax), and enhanced the expression of antiapoptotic factor (Bcl-2). Upregulated miR-124 inhibited the expression of EGR1, by which mechanism miR-124 reduced the neurological deficits induced by isoflurane in neonatal rats through inhibiting apoptosis of hippocampal neurons.